The crux of the issue will probably continue to be battery technology, for a while. The latest Apple Watches have basically everything you already want, includi

The crux of the issue will probably continue to be battery technology, for a while. The latest Apple Watches have basically everything you already want, including GPS & Cellular. They're not designed to be master devices though, since the watch formfactor is really hard to get much done on without some sort of master device for login, etc. Longer and more intensive use (more mapping, more calls) would probably kill the battery in nothing flat. While they're really good smart watches, they already struggle to keep up with the cpu/power/battery tradeoffs that are required for even a reasonable 1-day life. Some basic things you wouldn't expect, like crypto for HTTPS, take a LOT of work on a tiny wrist-mounted CPU.